the first lady wore a gown by jason wu, the same designer she wore to the 2009 inaugural ball. performances including alicia keys, brad paisley, marc anthony and jamie foxx who performed "i can't stop loving you" for vice president biden and his wife, jill. earlier the president tipped his hat to the military in attendance. >> this little party is just another way to say something we can never say enough. thank you. thank you for volunteering. thank you for stepping up. thank you for keeping us strong. thank you for always making us proud. i have no greater honor than being your commander in chief. >> four years ago the president and first lady attended ten official inaugural balls. last night the inaugural committee held just two. the lowest number of balls for an inauguration since the eisenhower administration. the highlight of the day, however, took place on the steps of the capitol where the president offered his second-term challenge to the nation. joined from the principles of the founding fathers in pivotal moments from america's history. president obama delivered an im